PARADISE ISLAND, Bahamas (AP) -- The notion defies logic. Iowa had not led for a single second all night long. The guy who was single-handedly carrying the offense was gone with a nasty leg cramp. The deficit was four and time was running out.

Somehow, that meant the Hawkeyes had Xavier right where they wanted.

Never led in regulation, never trailed in overtime, and still unbeaten. Such is the story for No. 23 Iowa, which rallied from a 15-point, second-half deficit to beat Xavier 77-74 in overtime at the Battle 4 Atlantis quarterfinals Thursday night.

''You know what's interesting about our team, and I mean this sincerely, we've got so many different players who can score,'' Iowa coach Fran McCaffery said.

The Hawkeyes needed them all, too.

Devyn Marble scored 30 points before leaving with a right leg cramp, a problem that affected Xavier standout Semaj Christon as well. The converted ballroom that serves as the arena for this event has a low ceiling, hot lights and it was packed with people seated not far from the floor. So yes, even indoors - and on a relatively cool day in the Bahamas - the elements were a factor.

Iowa (6-0) handled them all. Zach McCabe scored 11 points, and Gabriel Olaseni had 10 points and 11 rebounds for the Hawkeyes. Aaron White's 10-point night ended with a clutch tip-in with 1:40 left in overtime, and the Hawkeyes held on from there.

''Coach trusted us,'' Olaseni said.

Xavier (5-1) had three 3-point tries all bounce off the rim in the final 10 seconds. Justin Martin led the Musketeers with 15 points, Christon added 14, Myles Davis scored 12 and Matt Stainbrook finished with 11.

Iowa will meet Texas-El Paso in Friday's semifinals, with Xavier facing Tennessee in the consolation round.

Xavier led by 15 early in the second half and wasted it all. The Musketeers had 55 points in the first 28 minutes of regulation, then 14 in the final 12 minutes before the extra session.

''The wheels fell off,'' Xavier coach Chris Mack said.

That they did, even though Iowa was making life pretty easy on the Musketeers. The Hawkeyes missed 13 of their first 15 shots of the second half, and even gave Xavier two bonus points during intermission. As the teams were leaving the floor for halftime, McCaffery earned a technical foul for arguing with the referees, so 37-30 became 39-30 after a pair of free throws before the second half started.

Xavier's lead was 55-42 with 12 minutes left. That's when Iowa remembered to start putting the ball through the hole.

A 3-pointer by Marble, a dunk from White and another 3 from Marble - all in the span of about 70 seconds - got Iowa right back into things. Another stop led to a possession where Marble hit a pair of free throws with 8:09 left, and Melsahn Basabe's dunk in transition capped a 12-0 run that drew Iowa within 55-54.

Xavier pushed the lead back to six, with Stainbrook getting a three-point play and assisting on another basket, before Iowa closed within one yet again.

With 2:06 left in regulation and Iowa down four, the Hawkeyes figured to have lost their best shot at a comeback.

Marble, who was getting his right calf worked on during at least one previous timeout because of cramping, went down near his team's bench because of another cramp, writing and screaming in obvious pain.

He had 30 of Iowa's 63 points at the time, and without him, the Hawkeyes' comeback chore figured to get considerably tougher.

No Marble?

No problem, somehow.

Olaseni made a pair of free throws, Mike Gesell hit a 10-footer with 1:40 left after a turnover, and Iowa had finally tied the game. Both teams wound up missing chances at the end of regulation and to the extra session they went, tied at 69-all.

Before the game was 4 minutes old, Iowa was facing what was its biggest deficit of the season.

Christon had a pair of early dunks for Xavier, the Hawkeyes came out cold, and it was 11-2 Musketeers right out of the gate. In Iowa's first five games, the largest lead by any opponent was seven points.